1 files changed, 23 insertions, 6 deletions

diff --git a/src/menu.c b/src/menu.c
index 2c787e00b6f..f741d686cd1 100644
--- a/src/menu.c
+++ b/src/menu.c
@@ -1036,8 +1036,8 @@ find_and_return_menu_selection (struct frame *f, bool keymaps, void *client_data
 }
 #endif  /* HAVE_NS */
 
-static int
-item_width (const char *str)
+int
+menu_item_width (const char *str)
 {
   int len;
   const char *p;
@@ -1104,7 +1104,7 @@ into menu items.  */)
           if (XINT (pos) <= col
               /* We use <= so the blank between 2 items on a TTY is
                  considered part of the previous item.  */
-              && col <= XINT (pos) + item_width (SSDATA (str)))
+              && col <= XINT (pos) + menu_item_width (SSDATA (str)))
             {
               item = AREF (items, i);
               return item;
@@ -1160,7 +1160,7 @@ event (indicating that the user invoked the menu with the mouse) then
 no quit occurs and `x-popup-menu' returns nil.  */)
   (Lisp_Object position, Lisp_Object menu)
 {
-  Lisp_Object keymap, tem;
+  Lisp_Object keymap, tem, tem2;
   int xpos = 0, ypos = 0;
   Lisp_Object title;
   const char *error_name = NULL;
@@ -1169,6 +1169,7 @@ no quit occurs and `x-popup-menu' returns nil.  */)
   Lisp_Object x, y, window;
   bool keymaps = 0;
   bool for_click = 0;
+  bool kbd_menu_navigation = 0;
   ptrdiff_t specpdl_count = SPECPDL_INDEX ();
   struct gcpro gcpro1;
 
@@ -1202,6 +1203,22 @@ no quit occurs and `x-popup-menu' returns nil.  */)
             for_click = 1;
             tem = Fcar (Fcdr (position));  /* EVENT_START (position) */
             window = Fcar (tem);             /* POSN_WINDOW (tem) */
+            tem2 = Fcar (Fcdr (tem));        /* POSN_POSN (tem) */
+            /* The kbd_menu_navigation flag is set when the menu was
+               invoked by F10, which probably means they have no
+               mouse.  In that case, we let them switch between
+               top-level menu-bar menus by using C-f/C-b and
+               horizontal arrow keys, since they cannot click the
+               mouse to open a different submenu.  This flag is only
+               supported by tty_menu_show.  We set it when POSITION
+               and last_nonmenu_event are different, which means we
+               constructed POSITION by hand (in popup-menu, see
+               menu-bar.el) to look like a mouse click on the menu bar
+               event.  */
+            if (!EQ (POSN_POSN (last_nonmenu_event),
+                     POSN_POSN (position))
+                && CONSP (tem2) && EQ (Fcar (tem2), Qmenu_bar))
+              kbd_menu_navigation = 1;
             tem = Fcar (Fcdr (Fcdr (tem))); /* POSN_WINDOW_POSN (tem) */
             x = Fcar (tem);
             y = Fcdr (tem);
@@ -1434,8 +1451,8 @@ no quit occurs and `x-popup-menu' returns nil.  */)
   else
 #endif
   if (FRAME_TERMCAP_P (f))
-    selection = tty_menu_show (f, xpos, ypos, for_click,
-                               keymaps, title, &error_name);
+    selection = tty_menu_show (f, xpos, ypos, for_click, keymaps, title,
+                               kbd_menu_navigation, &error_name);
 
 #ifdef HAVE_NS
   unbind_to (specpdl_count, Qnil);